In the related art, with respect to a method of driving a rotary press-in steel pipe pile having a helical blade provided at a distal end of a steel pipe into the ground by applying a rotating force to the rotary press-in steel pipe pile, many methods have been proposed. For example, a steel pipe pile described in Patent Document 1 is provided with an drilling edge provided at a lower end of a steel pipe, a lower helical blade provided on the outer periphery of a lower portion of the steel pipe and having an outer diameter of twice the diameter of the pile, and an upper helical blade provided on the proximal end side of the steel pipe. Ground is drilled by the drilling edge, and a soil removal plate for removing drilled soil entered the bottom surface side of each helical blade to the outside of each helical blade is provided.
Further, a rotary press-in steel pipe pile described in Patent Document 2 has a steel pipe having a distal end portion formed in a helical shape, a lower helical blade made by helically forming a substantially circular steel plate larger than the diameter of the steel pipe along the distal end shape of the steel pipe, and an upper helical blade provided on the proximal end side of the steel pipe and made by helically forming a doughnut-shaped steel plate.
Further, in a rotary press-in steel pipe pile described in Patent Document 3, a distal end of a steel pipe is formed in a helical shape, a single blade protrudes to the inside and the outside of a distal end portion of the steel pipe, and the angle between a portion protruding to the outside and a steel pipe main body is made to be an approximately right angle. Further, a sectorial gap is formed in this blade, and thus the movement of soil while rotationally driving the steel pipe pile can be carried out smoothly.